generic BLOB support

[Carlos Villegas <ca...@uniscope.jp>]

Hi,

I'm writing a store based on OJB for the Jakarta Slide WebDAV server and 
one of the main reasons for using OJB is to get database independence. 
So far it's been ok but now I'm at the point where I need to store the 
file contents into the database. Naturally I want to use the BLOB data 
type and I want to make sure that the BLOB is not brought into memory 
but accessed via io streams. However, it seems that not all databases 
have a true BLOB type or good JDBC support for it but they all seem to 
have some support for large objects.
So, what would be the best way to do this?
I haven't actually tested anything but just looking at PostgreSQL, for 
instance, it doesn't seem that JDBC type BLOB mapped to native bytea 
type would work, or BLOB to oid (pg large object interface). Note that I 
want to have a fixed java data type across all databases.
Any suggestions?

Carlos

---------------------------------------------------------------------
To unsubscribe, e-mail: ojb-user-unsubscribe@db.apache.org
For additional commands, e-mail: ojb-user-help@db.apache.org

Re: generic BLOB support

[Thomas Dudziak <to...@gmail.com>]

BLOB is a JDBC datatype that is mapped by the concrete JDBC driver
(which is database specific) to the real database SQL type. In the
case of PostgreSQL, the jdbc driver maps it to bytea. You can see the
difference in the related OJB files: in repository.xml you use BLOB as
the datatype, and in the database schema (Torque files or SQL calls),
you use the corresponding database type, e.g. bytea for PostgreSQL.

So, IMO your best bet is using BLOB, e.g. via java.sql.Blob objects.
I'm not sure whether BLOB support is required for some JDBC level
(perhaps 2.0 ?), but every JDBC-supported database that has a large
binary datatype should have a BLOB-supporting JDBC driver.

Tom

---------------------------------------------------------------------
To unsubscribe, e-mail: ojb-user-unsubscribe@db.apache.org
For additional commands, e-mail: ojb-user-help@db.apache.org